1. Field of the Invention
The present invention relates to a method of manufacturing an optical element and a method of manufacturing a resin-sealed light emitting element as well as an optical element, a resin-sealed light emitting element and a planar light source device.
2. Related Background Art
Among light emitting elements, a light emitting diode (LED) element emits light as follows. Specifically, a p type semiconductor and an n type semiconductor are combined to each other, and then connected to an anode and a cathode, respectively. Subsequently, voltage is applied in the forward direction, and positive holes (holes) in the p type semiconductor are combined to electrons in the n type semiconductor near the pn junction, and thereby light is emitted.
The LED in which the LED element is sealed with resin is used for a projector and a backlight for a display. For example, International Publication No. WO03/107319 (WO 2003-107319 A) discloses a technique in which: LEDs for three primary colors, blue, green and red, are arranged; light emitting elements project the colored lights onto a distant liquid crystal panel to produce white light; and the white light is utilized as a backlight for a display.
In such an applied technique as described in WO 2003-107319 A, LED elements are combined to optical members molded from a sealing resin so as to function in any case. Accordingly, it is important to accurately position LED elements and the optical members in relation to each other. Moreover, it is also important to orderly dispose multiple LEDs and other optical elements in array.
However, there are the following problems in such a technique. The operation of accurately positioning the LED elements and the optical members molded from the sealing resin is inefficient. Moreover, it is particularly difficult to mold a thermosetting resin with a high refractive index into a finer size at the stage of polymerization. When resin-sealed light emitting elements are manufactured by combining the light emitting elements, such as the LED elements, to the optical members, such as a lens made of the thermosetting resin, the assembly is difficult. This is because it is impossible to form positioning means on the optical members, the positioning means being for accurately positioning both the light emitting elements and the optical members in relation to each other. Furthermore, in the case of arranging the multiple LEDs and the other optical elements in array, it is necessary to position the optical members molded from the sealing resin in relation to the multiple LED elements which are fixed to the surface of an element substrate in a predetermined alignment. This adds an even more inefficient operation to the manufacturing process.